Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology, Barcelona, 08028, Spain.
Networking Biomedical Research Center (CIBER), Madrid, 28029, Spain.
Nat Commun. 2018 Dec 4;9(1):5157. doi: 10.1038/s41467-018-07499-x.
Despite the importance of electron transfer between redox proteins in photosynthesis and respiration, the inter-protein electron transfer rate between redox partner proteins has never been measured as a function of their separation in aqueous solution. Here, we use electrochemical tunneling spectroscopy to show that the current between two protein partners decays along more than 10 nm in the solution. Molecular dynamics simulations reveal a reduced ionic density and extended electric field in the volume confined between the proteins. The distance-decay factor and the calculated local barrier for electron transfer are regulated by the electrochemical potential applied to the proteins. Redox partners could use electrochemically gated, long distance electron transfer through the solution in order to conciliate high specificity with weak binding, thus keeping high turnover rates in the crowded environment of cells.
尽管电子在光合作用和呼吸作用中的氧化还原蛋白之间的转移很重要，但氧化还原伴侣蛋白之间的蛋白间电子转移速率从未在水溶液中作为它们分离的函数进行过测量。在这里，我们使用电化学隧道光谱法表明，两个蛋白伴侣之间的电流在溶液中沿 10nm 以上的距离衰减。分子动力学模拟揭示了在蛋白之间限制的体积内离子密度降低和电场扩展。距离衰减因子和计算出的电子转移局部势垒受施加在蛋白上的电化学势调节。氧化还原伴侣可以通过溶液中的电化学门控长距离电子转移来协调高特异性和弱结合，从而在细胞拥挤的环境中保持高周转率。
